P0171 Control module software needs to be updated, Vacuum leaks (intake manifold gaskets, vacuum hoses, PCV hoses, etc.), Mass air flow sensor, Plugged fuel filter or weak fuel pump, Plugged or dirty fuel injectors
Control module software needs to be updated: In some cases, the engine control module software may need to be updated to address known issues or bugs that can cause the P0171 DTC.
Vacuum leaks: Vacuum leaks in the intake manifold gaskets, vacuum hoses, PCV hoses, or other components can allow unmetered air to enter the engine, causing a lean condition. Inspect these components for any signs of damage or wear and replace as necessary.
Mass air flow sensor: A faulty or dirty mass air flow (MAF) sensor can cause incorrect readings of the amount of air entering the engine, leading to a lean condition. Clean or replace the MAF sensor as necessary.
Plugged fuel filter or weak fuel pump: A plugged fuel filter or weak fuel pump can restrict the flow of fuel to the engine, causing a lean condition. Check the fuel filter and fuel pressure to determine if they are within specifications.
Plugged or dirty fuel injectors: Dirty or clogged fuel injectors can restrict the flow of fuel into the engine, causing a lean condition. Have the fuel injectors inspected and cleaned or replaced as necessary.
If you are experiencing the P0171 DTC, it is recommended that you take your vehicle to a qualified mechanic or dealership for diagnosis and repair. They will be able to perform a thorough inspection of the fuel system and associated components, and determine the exact cause of the issue. Depending on the underlying problem, repairs may include updating the engine control module software, repairing or replacing vacuum hoses, PCV hoses, or intake manifold gaskets, cleaning or replacing the MAF sensor, replacing the fuel filter or fuel pump, or cleaning or replacing the fuel injectors.
